1. Field of the Invention
The present invention relates to a fire protecting structure of a channel portion wherein a long flexible pipe such as a cable insertion pipe passage and a plastic pipe for supplying and exhausting water is inserted into a fire partition such as a floor and a wall, and the like.
2. Description of the Related Art
In factories or buildings, in a case where a through hole is formed in a fire partition such a floor or a wall and a plastic piping such as a cable insertion pipe passage and a plastic pipe for supplying and exhausting water, and the like is inserted therein, there is required a fire protection, for example, refractory materials are filled in a space between the through hole and the plastic piping.
FIG. 1A shows a conventional typical fire protecting structure of a channel portion in the above-mentioned places. In the drawing, reference numeral 10 denotes a plastic piping such as a plastic pipe, and the like. The plastic piping 10 is inserted into a through hole 12 of a wall 11, which is a fire partition. Noncombustible fiber 13 such as rock wool is filled in a space between an outer periphery of the plastic piping 10 and an inner wall of the through hole 12. In both sides of the through hole, a refractory plate 14 formed of calcium silicate is arranged. The plastic piping 10 is fixed by a refractory seal member 15 and at the same time the channel portion is also sealed. FIG. 1B shows the fire partition in a case where the fire partition is a floor 15. In this case, a plastic piping 10 is inserted in the through hole 12 formed in the floor 15. The heat expandable refractory material 16 is wound on the plastic piping 10. The support 17 is attached to the bottom surface of the floor 15 so as to support the heat expandable refractory material 16. The putty is packed in the through hole 12. The above-structured fire protecting structure of the channel portion has been highly evaluated since it exhibits fire-resistance for about two hours. Moreover, the above-structured fire protecting structure of the channel portion can be applied to the case in which the plastic piping 10 is a plastic flexible wire pipe 20 in which an electric wire and a cable 22 are inserted as shown in FIG. 2 or a plastic pipe for supplying and exhausting water.
However, the following problems are found in the fire protecting structure of the channel portion of the plastic piping as shown in FIG. 1A.
First of all, since the refractory plate 14 is fixed to the wall 11 or noncombustible fiber 13 is filled the through hole 12 of the wall 11, the construction working becomes very complicated and working efficiency is reduced. Moreover, there is a possibility that workers will suck in flying noncombustible fiber 13 during the filling of the noncombustible fiber 13 in the through hole 12. This is unfavorable in view of the working conditions.
Second, in a case where the plastic flexible wire pipe 20 as shown in FIG. 2 is used as plastic piping 10 to be inserted, the flexible wire pipe 20 having a large diameter is used in order to reserve a space for increasing electric wires. Due to this, the electric wire 22 is not closely provided in the interior portion. Particularly, at the beginning when a preliminary plastic flexible wire pipe is laid, there is provided no electric wire therein. Therefore, the interior portion becomes completely hollow. Regarding the plastic pipe for supply and exhausting water, the similar matter can be pointed out. Therefore, as shown in FIG. 3, if a fire breaks out, the spaces of these pipe and the hollow portions becomes fire passing ways, and no fire protection effect is exhibited. Moreover, polyethylene or polyvinyl chloride, which easily burns, is used for the coating materials of the inserted electric wires, the plastic flexible wire pipe or the plastic pipe for supplying and exhausting water. Due to this, the fire rapidly spreads through the plastic flexible wire pipe or the plastic pipe.
Moreover, in the conventional fire protecting structure of the channel portion of the plastic piping in the fire partition there is a possibility that the refractory plate 14 for sealing the through hole is liable to detach due to permeation of leakage of water or rainwater, or an earthquake or the shaking, and the performance of the fire protection will be lost.